Only add divider when it need to show

By previous memory patch, the divider will always call update when
enter split when means it always add divider view when showing. So
we can reduce some update call to avoid any unnecessary surface
memory allocate.

Fix: 150190730
Test: Check split mode rotate normally and dump SF to check divider
      memory status
Change-Id: Idb39cefe0168e9e5e11ce0e13438a24f84cbb9f4

core/java/android/view/WindowlessWindowManager.java

@@ -41,7 +41,6 @@ public class WindowlessWindowManager implements IWindowSession {
     private final static String TAG = "WindowlessWindowManager";
 
     private class State {
-        //TODO : b/150190730 we should create it when view show and release it when view invisible.
         SurfaceControl mSurfaceControl;
         WindowManager.LayoutParams mParams = new WindowManager.LayoutParams();
         int mDisplayId;

packages/SystemUI/src/com/android/systemui/stackdivider/Divider.java

@@ -253,7 +253,9 @@ public class Divider extends SystemUI implements DividerView.DividerCallbacks,
             mSplitLayout.mSecondary = new Rect(mRotateSplitLayout.mSecondary);
             mRotateSplitLayout = null;
         }
-        update(newConfig);
+        if (isSplitActive()) {
+            update(newConfig);
+        }
     }
 
     Handler getHandler() {
@@ -328,11 +330,6 @@ public class Divider extends SystemUI implements DividerView.DividerCallbacks,
         mHandler.post(this::removeDivider);
     }
 
-    void onTasksReady() {
-        mHandler.post(() -> update(mDisplayController.getDisplayContext(
-                mContext.getDisplayId()).getResources().getConfiguration()));
-    }
-
     private void updateVisibility(final boolean visible) {
         if (DEBUG) Slog.d(TAG, "Updating visibility " + mVisible + "->" + visible);
         if (mVisible != visible) {
@@ -524,7 +521,7 @@ public class Divider extends SystemUI implements DividerView.DividerCallbacks,
 
     void ensureMinimizedSplit() {
         setHomeMinimized(true /* minimized */, mSplits.mSecondary.isResizable());
-        if (!isDividerVisible()) {
+        if (mView != null && !isDividerVisible()) {
             // Wasn't in split-mode yet, so enter now.
             if (DEBUG) {
                 Slog.d(TAG, " entering split mode with minimized=true");
@@ -535,7 +532,7 @@ public class Divider extends SystemUI implements DividerView.DividerCallbacks,
 
     void ensureNormalSplit() {
         setHomeMinimized(false /* minimized */, mHomeStackResizable);
-        if (!isDividerVisible()) {
+        if (mView != null && !isDividerVisible()) {
             // Wasn't in split-mode, so enter now.
             if (DEBUG) {
                 Slog.d(TAG, " enter split mode unminimized ");

packages/SystemUI/src/com/android/systemui/stackdivider/SplitScreenTaskOrganizer.java

@@ -113,8 +113,6 @@ class SplitScreenTaskOrganizer extends TaskOrganizer {
                 t.setColor(mSecondaryDim, new float[]{0f, 0f, 0f});
                 t.apply();
                 releaseTransaction(t);
-
-                mDivider.onTasksReady();
             }
         }
     }